Oh my... lower psi in car tires on Spyder's really works!

[Mikey]

Chirping is the sound you get to tell you that you are on the hairy edge, of that tire's traction for the set up! Push it any harder and you will see where you been instead of where you are going! Driving Autocross taught me that, I have done a few loopy loops!! Hell of a lot of fun with a car, not so much with a BIKE!

 

[Sarge707]

I have 22-23 in my Kumho Ecsta rear on my F3 and it slips when I downshift pretty easy. Wears great but stock tire was better. IMO

 

[BLUEKNIGHT911]

I have 22-23 in my Kumho Ecsta rear on my F3 and it slips when I downshift pretty easy. Wears great but stock tire was better. IMO

Because that Kumho is a Car tire at your PSI ....it's 4 to 5 lbs psi to high ..... Ask Peter .... Mike :thumbup:

 

[Wahrsuul]

Many people seem to think that the Max Inflation listed on the tire is what they're supposed to be at. I've gotten into arguments with people over that when I tell them to use the decal inside the driver's door (usually). Tire manufacturer's don't know what vehicle that tire is going on or for what use.

If you want to get really precise, do the chalk or water test to set the pressures.

 

[2dogs]

So few folks know about the water or chalk test. It's so simple and quick.

 

[sledge]

I have put the new Quatrac's on the Front/Back.

165/60/15 on the front

205/60/15 on the rear.

16 is the magic number all of the way around for me and if I go to 17-18 my rear tire starts chirping when going around corners.

Well...... this is the first thing I have heard or seen about this, I have been hearing a little chirping noise when pulling out and cornering ... I thought it was the drive belt.
But now that you've said this, I am pretty sure that's what I am hearing too... Thank you for the Info.

 

[Knizar]

Well...... this is the first thing I have heard or seen about this, I have been hearing a little chirping noise when pulling out and cornering ... I thought it was the drive belt.
But now that you've said this, I am pretty sure that's what I am hearing too... Thank you for the Info.

The chirping could also be your wheel bearings! "Just something to think about".......:thumbup:...Bill

 

[Frankf]

So few folks know about the water or chalk test. It's so simple and quick.

Explain.....

 

[2dogs]

Explain.....

Make a chalk line across your tire in the area of the valve stem. (Makes it easier to find.) Drive a short distance and check the line. It should disappear evenly. If not adjust PSI so it does.

 

[BLUEKNIGHT911]

what was the consensus psi? front and back with car tires? I am definitely on aggressive side.

" Consensus " - Do you think at a race track they poll the Entire Pit crew to decide what PSI they will use. ... To me " consensus is similar to S.W.A.G. ..... good luck ....Mike :thumbup:

 

[Peter Aawen]

Make a chalk line across your tire in the area of the valve stem. (Makes it easier to find.) Drive a short distance and check the line. It should disappear evenly. If not adjust PSI so it does.

I generally recommend a big wide band of chalk instead of just a line, 2dogs - preferably at least covering 3 tread blocks width at the circumference & extending from those 3 blocks right across the tread face!

This is to also show the wear pattern on the tread blocks themselves; cos if you just put a line across a single tread block, especially one on the edge of the tread face, the wear pattern on the edge blocks in particular may 'heel/toe' or 'scallop', and that could mean the narrow strip of that tread block where the line is just gets completely missed, making the viewer think their pressure is still too high when it may not be; or vice versa!! :shocked: . With a big wide band of chalk mark across the tread face, you'll be able to see PDQ what your tread wear pattern is doing on any of those tread blocks, and if you do that soon enough after fitting new tires, that might mean you catch the developing wear pattern rather than an established wear pattern, so you juuust might be early enough to rectify things & save that tire or set of tires from early retirement due to abnormal tread wear!! :banghead:

Just Sayin' :thumbup:

 

[PW2013STL]

So few folks know about the water or chalk test. It's so simple and quick.

I told someone at Spyderfest how to do this and he was amazed.

 

[ButterSmooth]

Using the 'load and load rating' method I arrived at somewhat different pressures.

Rear with a Yoko 92H (1400# rating @51psi) and 450# load (road scale) calculates to ~16psi. 1400 / 51 = 27.45 #load per psi. 450# / 27.45 = 16.39psi.

Front Vredstein 980# rating @51#, 375# load (750# on front) calculates to 19.5psi. 980 / 51 = 19.21# load per psi. 375# / 19.21 = 19.5psi.

The smaller front tires with the higher front load require more pressure. At 16psi my fronts seemed fine, but emergency maneuvers (rock dodge) made them collapse under the load. 14psi sounds scary soft to me.

 

[2dogs]

I generally recommend a big wide band of chalk instead of just a line, 2dogs - preferably at least covering 3 tread blocks width at the circumference & extending from those 3 blocks right across the tread face!

This is to also show the wear pattern on the tread blocks themselves; cos if you just put a line across a single tread block, especially one on the edge of the tread face, the wear pattern on the edge blocks in particular may 'heel/toe' or 'scallop', and that could mean the narrow strip of that tread block where the line is just gets completely missed, making the viewer think their pressure is still too high when it may not be; or vice versa!! :shocked: . With a big wide band of chalk mark across the tread face, you'll be able to see PDQ what your tread wear pattern is doing on any of those tread blocks, and if you do that soon enough after fitting new tires, that might mean you catch the developing wear pattern rather than an established wear pattern, so you juuust might be early enough to rectify things & save that tire or set of tires from early retirement due to abnormal tread wear!! :banghead:

Just Sayin' :thumbup:

My father-in-law showed me that trick years ago. He used to build custom trailers and to determine the PSI to recommend to his customers he used the chalk method. He did use a large piece of chalk the size kids use on sidewalk games. That piece of chalk is still sitting on a shelf in the shop. I wonder about using a wide strip of white spray paint. He told me he was told about that chalk method back during WWII when you had to use ration stamps to purchase tires. Tires had to last a long long time between purchases so you didn't want to wear them out too soon.

 

[Wahrsuul]

Spray paint might work too, but then you have paint down in the tread till it wears off, and paint on the driveway when it comes off the tire. If you have a concrete driveway, a thin layer of water work too. A thin layer of water on the concrete, ride through slowly and see what the tread pattern looks like.

 

[newdave]

Spray paint might work too, but then you have paint down in the tread till it wears off, and paint on the driveway when it comes off the tire. If you have a concrete driveway, a thin layer of water work too. A thin layer of water on the concrete, ride through slowly and see what the tread pattern looks like.

Grandpa showed me this one in the '70s. Works every time!

 

[2dogs]

Spray paint might work too, but then you have paint down in the tread till it wears off, and paint on the driveway when it comes off the tire. If you have a concrete driveway, a thin layer of water work too. A thin layer of water on the concrete, ride through slowly and see what the tread pattern looks like.

Yes, concrete. Not blacktop. Blacktop is not smooth enough and do it in the shade because the water evaporates fast.

 

[FrogmanDave]

I generally recommend a big wide band of chalk instead of just a line, 2dogs - preferably at least covering 3 tread blocks width at the circumference & extending from those 3 blocks right across the tread face!

That's some darn good information there!

 

[Peter Aawen]

Using the 'load and load rating' method I arrived at somewhat different pressures.

Rear with a Yoko 92H (1400# rating @51psi) and 450# load (road scale) calculates to ~16psi. 1400 / 51 = 27.45 #load per psi. 450# / 27.45 = 16.39psi.

Front Vredstein 980# rating @51#, 375# load (750# on front) calculates to 19.5psi. 980 / 51 = 19.21# load per psi. 375# / 19.21 = 19.5psi.

The smaller front tires with the higher front load require more pressure. At 16psi my fronts seemed fine, but emergency maneuvers (rock dodge) made them collapse under the load. 14psi sounds scary soft to me.

Don't forget that's for your loads & your choice of tires/tire size, Butters - other peoples may be different! :lecturef_smilie:

And it's probably worth bearing in mind that the tire itself (not incl the tread! ) is effectively just a bag that carries the load put on it - use a smaller bag for a given load & it'll need more pressure than a larger bag asked to carry that same given load! :thumbup: . So if you go bigger (or stronger ) in the tire you're running, you'll likely need a lower pressure; wheras if you go smaller (or weaker ) you'll generally need a higher pressure! hyea: ..... And only then can you start to work on the problem of how to get the tread up to its operating temp for it to provide the traction you need!

Simples, innit?! :cheers:

 

[ButterSmooth]

Don't forget that's for your loads & your choice of tires/tire size, Butters - other peoples may be different! :lecturef_smilie:

And it's probably worth bearing in mind that the tire itself (not incl the tread! ) is effectively just a bag that carries the load put on it - use a smaller bag for a given load & it'll need more pressure than a larger bag asked to carry that same given load! :thumbup: . So if you go bigger (or stronger ) in the tire you're running, you'll likely need a lower pressure; wheras if you go smaller (or weaker ) you'll generally need a higher pressure! hyea: ..... And only then can you start to work on the problem of how to get the tread up to its operating temp for it to provide the traction you need!

Simples, innit?! :cheers:

:bowdown::bowdown::bowdown: Couldn't agree more... I just can't afford that many words! Thanks for filling in the gaps!:thumbup: